A drum cleaner in a drum unit removes toner from a photosensitive drum. A waste-toner conveyance pipe has a waste-toner discharge port and conveys toner removed from the photosensitive drum by the drum cleaner. A toner accommodation chamber accommodates toner to be supplied to a developing roller. A waste-toner accommodation chamber accommodates toner removed from the photosensitive drum. A toner cartridge rotatably moves relative to the drum unit between: a first position at which a waste-toner receiving port is separated from the waste-toner discharge port in a state where the toner cartridge is mounted on the drum unit; and a second position at which an internal space of the waste-toner accommodation chamber is in communication with an internal space of the waste-toner conveyance pipe through the waste-toner discharge port and the waste-toner receiving port in a state where the toner cartridge is mounted on the drum unit.